Effect of Multiple Freezing/Thawing Cycles on the Structural and Functional Properties of Waxy Rice Starch |
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| Authors: | Han Tao Juan Yan Jianwei Zhao Yaoqi Tian Zhengyu Jin Xueming Xu |
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| Institution: | 1School of Food Science and Technology, Jiangnan University, Wuxi, PR China;2State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, PR China;3Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, Wuxi, Jiangsu Province, China;National Taiwan University, TAIWAN |
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| Abstract: | The structural and functional properties of non-gelatinized waxy rice starch were investigated after 1, 3, 7, and 10 freezing/thawing cycles. Freezing caused an increasing damaged starch from 1.36% in native waxy rice starch to 5.77% in 10 freezing/thawing-treated starch (FTS), as evidenced by the cracking surface on starch granules. More dry matter concentration was leached, which was characterized by high amylopectin concentration (4.34 mg/mL). The leaching was accompanied by a decrease in relative crystallinity from 35.19% in native starch to 31.34% in 10 FTS. Freezing treatment also led to significant deviations in the functional characteristics, for instance decreased gelatinization temperature range, enthalpy, and pasting viscosities. The resistant starch content of 10FTS significantly decreased from 58.9% to 19%, whereas the slowly digested starch content greatly increased from 23.8% in native starch to 50.3%. The increase in susceptibility to enzyme hydrolysis may be attributed to porous granular surface, amylopectin leaching, and the decrease in the relative crystallinity caused by freezing water. |
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